Electromagnetic drive



Feb. 10, 1970 J. M. sEPKo ELECTROMAGNETIC DRIVE 2 Sheets-Sheet l FiledNov. .6, 1967 v llllmT` -illlim mgglm INVENTOR. JOSEPH. M. SEP/ 0Feb..10',1970 l J.M. smo l l3,494,453

l ELEGTROMAGNETIC DRIVE Filed Nov. e, 1967 2 sheets-sheet l2 se a/ "nl"l 04 www INVENTOR. JOSEP/l M. SEP/ 0 4 TTORNEYS United States Patent O3,494,453 ELECTROMAGNETIC DRIVE Joseph M. Sepko, Parma, Ohio, assignorto Eaton Yale & Towne Inc., Cleveland, Ohio, a corporation of Ohio FiledNov. 6, 1967, Ser. No. 680,894 Int. Cl. F16d 27/02; H01f 5/00 U.S. Cl.192-84 1 Claim ABSTRACT OF THE DISCLOSURE The present invention relatesto a new and improved electromagnetic drive and, particularly, to anelectromagnetic clutch having driving and driven members and anelectrical coil which is energizable to control the transmission oftorque between the driving and driven members.

The principal object of the present invention is the provision of a newand improved electro-magnetic drive having an electrical coil which isenergizable to control the transmission of torque between driving anddriven members and wherein the coil is electrically grounded in a highlypractical manner which is reliable in operation and simple inconstruction.

A further object of the present invention is the provision of a new andimproved electromagnetic drive which includes an electrical coil whichcontrols the transmission of torque between driving and driven membersand is supported by .one of the driving and driven members and rotatestherewith and wherein the drive is of a simpliiied construction with aminimum of electrical lead wires connected with the coil to effect thedelivery of electrical energy to the coil and grounding of the coil.

A still further object of the present invention is the provision of anew and improved electromagnetic clutch which includes driving anddriven members and an electrical coil for controlling the transmissionof torque between the driving and driven members and wherein theelectrical coil is grounded by an annular member having at least aportion thereof in electrical contact with a portion of the electricalcoil and with the driven member.

Another object of the present invention is the provision of a new andimproved electromagnetic cluth having a drive pulley which carries anelectrical coil which extends circumferentially of the axis of rotationof the pulley and wherein an annular ring member is press fit on thepulley member and has electrical contact with at least a portion of thecoil and operates to ground the coil to the pulley.

Further objects and advantages of the present invention will be apparentto those skilled in the art to which it relates from the followingdetailed description of a preferred embodiment thereof made withreference to the accompanying drawings forming a part of thisspecification and in which:

FIG. 1 is an elevational view of an electromagnetic clutch, partially insection, and which embodies the present invention;

FIG. 2 is an end view of the electromagnetic clutch of FIG. l, lookingat the electromagnetic clutch of FIG. 1 along the line 2 2 thereof;

3,494,453 Patented Feb. 10, 1970 ICC FIG. 3 is a cross-sectional view ofa part of the electromagnetic clutch of FIG. l;

FIG. 4 is a fragmentary sectional view on an enlarged scale .of aportion of FIG. 3; and

FIG. 5 is a sectional view taken approximately along the section line 55 of FIG. 3.

The present invention provides an improved electromagnetic drive of thetype which includes an electrical coil for controlling the transmissionof torque between driving and driven members. In particular, the presentinvention provides an electromagnetic clutch of a simplied construction.The present invention may be applied to electromagnetic clutches ofdifferent constructions and uses. For purposes of illustration, however,an electromagnetic clutch 10 is illustrated in the drawings.

The electromagnetic clutch 10 includes a driving member in the form of apulley 11 and a driven member in the form of a shaft 12. Torque istransmitted from the pulley 11 to the shaft 12 through a clutchmechanism which includes a torque-transmitting armature member 13 whichis drivingly connected to the shaft 12. The torque-transmitting member13 on rotation eiects rotation of the shaft12.

The torque is transmitted from the pulley 11 to the torquetransmittingmember 13 by a frictional engagement .of surface 13a on thetorque-transmitting member with a surface 15a on a cover member 15 whichis suitably secured by fasteners 16 to the pulley member 11.

The torque-transmitting member 13 has, as shown in FIG. l, a positionout of frictional engagement with the surface 15a on the cover member15, in which position no torque is transmitted from the pulley 11 to theshaft 12. The member 13 biased to the non-torque transmitting position,illustrated in FIG. l, by a plurality of spring members 20 which areconnected to a hub portion 21` and which bias the member 13 away fromengagement with the member 15. When the member 13 is out of engagementwith the member 15, the pulley 11 rotates vfreely with respect to theshaft 12 and to this end, the pulley is supported by a bearing assembly,generally designated 25,

for rotation relative to the shaft 12. The drive connection between thehub portion 21 and the shaft 12 may take many forms and will not bedescribed in detail since it is not important to the present invention.

The member 13 is moved from the position shown in FIG. 1 intodrive-transmitting relationship with the member 15 upon the energizationof an electrical coil 30 in a lwell known manner. The energization ofthe electrical coil 30 thus controls the transmission of torque from thepulley 11 to the shaft 12.

The electrical coil 30 is an annular coil member which extendscircumferentially of and fully encircles the axis of rotation of thepulley member 11 and shaft 12. The coil member 30 is located in anannular recess 31 in the pulley member 11 and is encapsulated by anepoxy compound, designated at 32, which functions as an insulatorbetween the coil 30 and body of pulley 11. The coil 30 is of the typewhich includes, as best shown in FIG. 5, a strip of electricalconductive material such as metal foil, which is wound around the pulley11 providing a series of layers 32a, 32b, 32e, 32d of electricalconductive material which layers are electrically insulated from eachother by insulating material between the adjacent layers and whichmaterial is designated 40. The number of layers of conductive materialmay vary. The thickness of each layer has been exaggerated for purposesof illustration. As an alternative, the use of strips of conductivematerial, the coil 30 could be comprised of coils of wire not shown andas is conventional.

Electrical energy is delivered to the coil 30 for effecting theenergization thereof through an electrical conductor means 45. Theelectrical conductor means 45 isl connected by a suitable connector 46to a slip ring 47. The slip ring 47 contacts an adjacent slip ring, notshown, which delivers electrical energy to the coil 30 through the slipring 47, the connection 46 and the conductor 45 to effect energizationof the coil 30. As best shown in FIG. 3, the connector 46 and theconductor 45 are also embedded in the insulating material 32. Moreover,an insulating ring 50 is supported on the pulley 11 and insulates theslip ring 47 from the body of the pulley 11.

In accordance with the present invention, the electrical coil 30 isgrounded to the body of the pulley member 11. The grounding of the coil30 is effected by a relatively simple construction which is highlyreliable in operation and extremely practical in view of the simplicityof the construction.

The means for grounding the coil 30 comprises an annular ring member 60which has a surface portion 62 which engages a portion 64 of theinnermost conductive layer 32a of the electrical coil 30. The ringmember 60 also has an annular inner surface 63 which engages an axiallyextending radially inner surface 11a of the recess 31 in the pulleymember 11. The annular ring member 60 encircles the axis of rotation ofthe shaft, 12 and is press fit onto the pulley member 11 andparticularly onto the annular surface 11a of the pulley member. The ring60 has a greater axial extent than the coil 30 (FIG. 4) so that the ring60 projects axially from the coil 30. This enables a radially extendingstop surface 70 on the ring 60 to engage a radially extending andaxially inner surface 71 of the recess 31 to position the coil 30 in aspaced apart relationship with the surface 71. The space between thecoil 30 and surface 71 is filled with the epoxy compound 32 to insulatethe coil 30 from the pulley 11. The ring 60 is made of a suitableelectrical conductive material so as to effect grounding of the coil 30to the body of the pulley 11. The grounding is effected due to theelectrical contact between the surface 62 of the ring and the innermostlayer 32a of conductive material, and the contact of the surface 63 ofthe ring with surface 11a of the pulley. The end of the layer 32a issuitably bonded to the ring 60 and is preferably insulated from the ring60 except at the end portion 64 thereof, as described above.

It should be noted that the particular construction described involvesthe use of a single slip ring 47 and a single lead wire leading to thecoil 30 from the slip ring 47. Since the grounding of the coil 30 iseffected through the ring member 60, the grounding of the coil 30`requires no additional leads from the coil 30 and no additional sliprings,

y Having described my invention, I claim: ,p

1. A drive assembly comprising a driving member, a driven member, meansfor transmitting torque between said driving and driven membersincluding an armature member drivingly connected to said driving memberto effect rotation ofsaid driving member upon rotation thereof, saidarmature member having a non-torque transmitting position with respectto said driving member and a torque transmitting position with respectto said driving member in which said armature member is in frictiona]driving engagement with surface portions on said driving member, saiddriving member defining a generally annular recess having an axiallyextending radially inner sur face and a radially extending axially innersurface, an annular electrical coil carried by said driving member insaid recess and energizable to effect movement of said armature memberfrom said non-torque transmitting position to said torque transmittingposition, electrical conductor means for delivering electrical energy tosaid electrical coil, and means for electrically grounding said elecltrical coil including an annular member electrically connected with saidcoil and having an inner surface disposed in engagement with saidaxially extending radially inner surface of said recess in said drivingmember to thereby provide an electrical connection between said annularmember and said driving member, said annular member projecting `axiallybeyond said electrical coil and having a continuous annular stop surfacepositioned in engage ment with said radially extending axially innersurface of said recess to position said electrical coil and annularmember in said recess with said electrical coil spaced apart from saidaxially inner surface of said recess, and epoxy compoundlling the spacebetween said electrical coil and axially inner surface of said recess.

. References Cited UNITED STATES PATENTS 2,560,868 7/1951 Hubert.2,973,850 3/1961 Iaeschke. 3,130,355 i 4/1964 Younger 335-299 3,214,08410/1965 Smirl.

MARK M. NEWMAN, Primary Examiner ALLAN D. HERRMANN, Assistant ExaminerU.S. C1. X.R. 335--282, 299

